This invention relates generally to electric motors and, more particularly, to controlling energization of electric motor windings for jetted bath tub and other user attended applications.
Known jetted bath tubs include a pump having a pump motor. The pump motor typically is an electric AC motor having start and run windings. Energization of the motor windings is controlled, at least in part, by an operator actuated control switch and a centrifugal switch. The operator actuated control switch for jetted bath tub applications typically is an air switch. The centrifugal switch controls cut-out of the motor start winding based on rotor speed during motor start-up.
One known air switch used in jetted tub applications is a "push to start, push to stop" type air switch. The known air switch includes a normally open snap action switch and a spring-biased actuator. The snap action switch is electrically connected in series with a power line and the common connection of the pump motor start and run windings. The snap action switch includes a movable, spring-biased button which extends from the snap action switch housing. The button is normally biased to be in a fully extended condition, and when the button is fully extended, the snap action switch is in an open state. When the button is fully depressed inward towards the housing, the snap action switch is in a closed state.
The spring-biased actuator includes an actuating arm movable from and between first and second positions. In the first position, the actuating arm does not contact the snap action switch button. In the second position, the actuating arm is in contact with, and fully depresses, the snap action switch button. The actuator is biased so that the actuator arm is normally in the first position.
The above described jetted bath tub pump motor application is referred to as a "user attended" application since the user has direct control over motor energization. There are many other "user attended" applications in addition to the jetted bath tub pump motor application. Although the above described motor has proven reliable and satisfactory, it would be desirable to reduce the cost of such motor, in terms of both component cost and assembly cost.
Accordingly, it would be desirable and advantageous to provide a low cost motor for jetted tub and other user attended applications. It would also be desirable and advantageous to provide such a low cost motor which is as reliable and safe as existing motors for user attended applications. It would further be desirable to eliminate the centrifugal switch for controlling energization of the motor start winding without adversely affecting motor operation.